When a transparent electrode such as ITO is applied to a device, patterning is needed. Since a transparent electrode formed of ITO with high conductivity has a large film thickness, a difference in height generated by etching becomes large. In a device in which an ultra thin film having a thickness of about 10 to several 10 nm is laminated, such as an organic solar cell or an organic EL device, defects such as short circuits at end portions are easily caused.
A transparent electrode formed by using metal nanowires such as silver nanowires has been recently suggested. A thickness of 100 nm or more is necessary to ensure a desired surface resistance in the transparent electrode formed by using metal nanowires. When the transparent electrode formed by using metal nanowires is patterned by etching, a large difference in height is caused similarly to the case of ITO. This leads to defects when an ultra thin film device is produced.